Slackening type blasting method

ABSTRACT

The present invention relates to a structure of slackening type blasting method and mat for excluding a part of sloping surface formed by base rock layer at one side or both sides of road upon establishing or expanding of the road or for excavating a part of middle portion of base rock layer made of non-free surface, and the invention is a slackening type blasting method which makes base rock layer of blasting region to be cracked whereby slackening from mother rock comprising: a blasting hole piercing step; a blasting lead wire connecting step; a blasting mat providing step which provides a steel plate member having a magnitude capable of covering whole of multiple blasting holes formed at each blasting region connected with said blasting lead wire, and a blasting mat of weight material in which elastic member surrounding around blasting holes of blasting region is attached to bottom portion of said steel plate member and weight reinforcing member made of I type or H type beam being a weight material is welded in grid shape at top surface; and a blasting step for blasting an explosive by operating by blasting a blasting means connected with blasting mother line drawn out of blasting region provided with said blasting mat.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to a slackening type blasting method for excluding by excavating a part of sloping surface formed by base rock layer at one side or both sides of road upon establishing or expanding of the road or for excavating a part of middle portion of base rock layer made of non-free surface.

[0002] In general, a case is necessarily happened which has to cut out sloped surface made of base rock layer in case of road construction work for establishing or expanding a remote hill road or a seashore road along mountain topography, in this case an excavating work of base rock slope is executed by utilizing a heavy duty equipment such as large type braker or excavator in order to prevent accident or damage of vehicle during passing, however since a problem is occurred in which a mechanical excavating work utilizing the heavy duty equipment such as large type braker is decreased in its excavating efficiency and a working term becomes longer in case where sloped base rock layer is hard base rock layer which is high in base rock strength, a construction work for cutting out the sloped rock surface is executed by a blasting construction working method utilizing an explosive as a means for solving this.

[0003] In accordance with the blasting construction working method of prior art, so called mobile type blasting method has been used in which an explosive filled to a number of blasting holes pierced to base rock layer is made to be blasted so that the base rock layer is completely released from mother rock via its blasting pressure whereby moving toward free surface.

[0004] However, since the mobile type blasting method of prior art as above description is made to increase the blasting pressure by using much explosive quantity in order to completely release the base rock layer of a part desired to cut out from the mother rock, there has been a problem that a blasting noise is big and not only a part of base rock broken upon blasting flies far away from blasting site to a remote place but also a blasting vibration coming from the blasting pressure is transmitted far away, according to this, the blasting has been done by laying a mat made of rubber material or straw bag etc. on the base rock surface so that the blasting noise is decreased and the broken base rock layer particles can not be flied, but since the rubber mat and the straw bag covered on the base rock layer fly away together with broken base rock particles by the blasting pressure, it is hard to expect an effect capable of largely decreasing the blasting noise and vibration, and in case when human dwelling houses and the like are located within 100 m near construction working site, there is problem that an application of blasting construction working method is difficult and a passing of neighbouring road should be isolated.

[0005] According to this, in case where the base rock layer made of hard rock has to be cut out with predetermined width at construction working site for establishing or expanding the mountain road or seashore road, and in case where dwelling houses and livestock facilities and the like are scattered within 100m from that construction working site and public establishment such as electric power transmission tower is established or else a road or rail road operated with vehicles or train are located at a place near the construction working site, when said mobile type blasting method is used, due to the exploding noise and the blasting vibration and the like produced upon blasting the base rock layer, not only the residents dwelling in residences are made to be surprised but also a casualty is occurred in which flying stones are flied into residence and building is shaken due to the blasting vibration or ground sinking phenomenon is appeared, and a problem is arisen which gives vast casualties to various animals bred in livestock facilities, and further there is a worry about producing casualties which induces an accident without doing safety operation at all due to influence of exploding sound, and not only casualties are given to a locomotive engine driver running on rail road and passenger riding on the train but also a blasting vibration according to explosion is given to rail road whereby derailing accident of train during running is induced, and therefore it is a present situation that the mobile type blasting method of prior art is extremely and limitedly used by considering various matters as above description.

OBJECT AND SUMMARY OF THE INVENTION

[0006] The present invention is invented by considering various problems of prior art as described above, and it is an object of the present invention to provide a slackening type blasting method which does not any influence to residence scattered at near of the construction working site or livestock facilities and public establishments in case when intending to cut out a part of free surface of base rock layer made of hard rock at an establishing construction working region or expanding construction working region of road such as mountain road or seashore road, and which do not give any casualty to a driver of vehicle running on road or a locomotive engine driver and passengers of train running on rail road and simultaneously making to cut out and catch by blasting the base rock layer by explosive.

[0007] Another object of the present invention is to provide a blasting mat which blocks an exposing of blasting pressure to exterior in case when executing the blasting work of base rock layer by said slackening type blasting method whereby preventing the blasting noise and flying stone to be discharged to exterior.

[0008] Still other object of the present invention is to make even a part of middle portion of base rock layer made of non-free surface to be possible to excavate to a predetermined depth by the blasting method.

[0009] In order to attain the objects as above, the present invention is characterized in that a base rock layer of blasting region is cracked by blasting pressure whereby slackening from mother rock comprising:

[0010] a blasting hole piercing step for partitioning by equally dividing the blasting region by predetermined distance toward lengthwise of base rock layer desired to excavate on horizontal top surface between free surface and cutting out surface of the base rock layer and then piercing a number of blasting holes having predetermined distance intervals at every said blasting region toward vertical down direction

[0011] a blasting lead wire connecting step for making a explosive inputted into the blasting hole pierced at said blasting hole piercing step to be divided by each blasting region so as to be possible to explode, and connecting the blasting lead wire so that the explosives inputted into the blasting holes of each blasting region can be successively exploded at predetermined order;

[0012] a blasting mat providing step for providing a blasting mat of heavy material in which a steel plate member having predetermined magnitude capable of covering whole of multiple blasting holes formed at each blasting region connected with said blasting lead wire and an elastic member surrounding around blasting holes of blasting region at said steel plate member are attached, and a heavy weight reinforcing member made of I type beam or H type beam is welded in grid shape to top surface and a blasting step for blasting an explosive by blasting the blasting means connected with blasting mother wire drawn out of blasting region provided with said blasting mat.

[0013] And, a structure of blasting mat used for attaining an object of the present invention is characterized by comprising:

[0014] a steel plate member having a thickness capable of bearing a blasting pressure of explosive inputted into the blasting hole;

[0015] an elastic member which is fixedly attached by bolt alongside bottom edge of said steel plate member and preventing the blasting noise, blasting gas and flying material of explosive inputted into each blasting hole of blasting region to be discharged to exterior; and

[0016] a heavy weight reinforcing member which is welded in a structure as grid window frame at top surface of said steel plate member, and which is made of steel frame material having heavy weight capable of bearing the blasting pressure.

BRIEF DESCRIPTION OF THE DRAWINGS

[0017]FIG. 1 is a side view of one embodiment for explaining the present invention, FIG. 2 is a plane view for showing a state of blasting hole arrangement of the present invention, FIG. 3 and FIG. 4 are cross sectional views showing a pierced hole depth of blasting hole of the present invention, FIG. 5 is a view of a blast executing state of the present invention, FIG. 6 is a perspective view for explaining a blasting mat structure of the present invention, FIG. 7 is a cross sectional view of blasting mat of the present invention, and FIG. 8 is a view of embodiment applying the present invention to non-free surface base rock layer.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

[0018] Explaining an embodiment of the present invention more in detail with reference to the accompanying drawings, it will be as follows.

[0019]FIG. 1 is a side view of one embodiment for explaining the present invention, FIG. 2 is a plane view showing a blasting hole arranging state of the present invention, FIG. 3 is a perspective view in cross section showing a filled state of blasting explosive of the present invention, FIG. 4 is a cross sectional view showing a blast executing state of the present invention, FIG. 5 is a perspective view for explaining a blasting mat structure of the present invention, FIG. 6 is a cross sectional view of blasting mat of the present invention, FIG. 7 is a cross sectional view of blast executing state of another embodiment of the present invention, and FIG. 8 is a view showing an embodiment applied with the present invention to non-free surface base rock layer.

[0020] A reference numeral 1 depicts a base rock layer formed at one side or both sides of road when doing an establishing construction working or doing expanding construction working for a mountain road or seashore road, and reference numeral 2 denotes a blasting mat according to the present invention.

[0021] Firstly, it will be explained with regard to the structure of blasting mat used for slackening type blasting method of the present invention.

[0022] The blasting mat 2 is constructed such that a steel plate member 21 having a thickness(more than 3 mm) capable of sufficiently bearing the blasting pressure of explosive provided to blasting hole, an elastic member 22 which is fixedly attached to edge portion of the steel plate member 21 whereby preventing a flying away of blasting noise and stones, and a weight reinforcing member 23 made of steel frame such as I type beam or H type beam being a weight body at top surface of the steel plate member 21 are welded to edge portion and in grid shape crossing its inner side, and a carrying wire 24 capable of carrying and moving by lifting the blasting mat 2 is fixedly attached at top surface of the steel plate member 21 or else a hooking member to its weight center portion so that the blasting mat 2 can be moved and carried by utilizing heavy duty equipment 3 such as large type braker or excavator.

[0023] In above description, the elastic member 22 attached to bottom edge portion of the blasting mat 2 is excellent in elasticity and easy to attach by bolt and the like, and it is preferable to use waste tire 22 a in recycling view of industrial waste material, and the waste tire 22 a sufficiently bears the blasting pressure together with vibration absorbing operation of the steel plate member upon blasting of explosive and simultaneously exterior discharging of blasting noise, blasting gas and flying away stones, and a close adherence to bumpy ground surface is made to be good so that what all direction of the steel plate member 21 is curled up whereby exposed to exterior is prevented.

[0024] Explaining a slackening type blasting method of the present invention which blasts and cuts out the portion between free surface 11 and cut our surface 12 of the base rock layer 1 from top layer to bottom layer in stepwise by using the blasting mat 2 as described above, it will be as follows.

[0025] A blasting region 14 is formed to horizontal top surface between free surface 11 and cut out surface of the base rock layer by equally dividing to predetermined region and then a number of blasting holes 15 are pierced at predetermined distance intervals at every each blasting region 14, and the blasting holes 15 are formed not only in the blasting region 14 but also in neighbouring blasting region 14 whereby pierced so as to maintain a predetermined distance even among the blasting holes 15 confronted each other.

[0026] Each blasting holes 15 formed to the blasting region 14 are pierced by previously establishing the piercing depth in considering dislocation structure of the base rock layer 1.

[0027] That is, as in FIG. 3, the blasting hole located at adjacent to free surface 11 and the blasting hole located at middle are deeply pierced while the blasting hole neat the cut out surface 12 is pierced little shallower whereby the blasting method can be executed, or as shown in FIG. 4, the blasting method can be executed by equally piercing the depth of all blasting holes.

[0028] An explosive 15 a as much as showing a blasting power about a degree capable of slackening the cutting out portion up to depth desired to cut out is filled to the blasting hole 15 formed to each of the blasting region 14 and then a blasting lead wire is connected, and at this moment, a quantity of explosive filled to the blasting hole 15 is filled only up to a degree(less than 0.4 kg/m²) which is weak than blasting pressure dropping or flying away the base rock layer 1 of the blasting region 14 and which is capable of producing only a crack so that the base rock layer 1 is slackened from mother rock, i.e., cut out surface 12, and said blasting lead wire is provided such that the explosives 15 a filled to the blasting hole 15 located at each blasting region 14 can be subsequently blasted at an time interval of extremely short time period(about 0.02 second to 0.05 second), and thus sand 15 b is filled to the blasting hole 15 after connecting the blasting lead wire to the explosives 15 a filled to the blasting hole 15.

[0029] As described above, after the explosive 15 a and the sand 15 b are filled to the blasting hole 15 of each blasting region 14, a blasting mother wire for blasting the explosive 15 a of each blasting hole 15 is connected to the blasting means and then the blasting mat 2 is lifted by heavy duty equipment 3 whereby top surface of the blasting region 14 desired to blast is covered, and since it is a state that a magnitude of the blasting mat 2 is bigger than the blasting region 14 and the waste tires 22 a being an elastic member 22 is closely adhered on top surface of the blasting region 14 in a state getting out the blasting hole 15 whereby pressed by weight of weight reinforcing member 23, even if top surface of the blasting region 14, i.e., the horizontal top surface 13 of base rock layer 1 is formed by uneven and irregularly bumpy surface, the waste tires 22 a of the elastic member 22 are closely adhered on top surface of bumpy blasting region 14 by weight of the weight reinforcing member 23, further when top of the blasting mat 2 is strongly pressed by boom bar of the heavy duty equipment 3, said waste tires 22 a are pressed and adhered on top of the blasting region 14 by more strong elasticity and at the same time even among mutually neighboring waste tires 22 a elastically closely adhered, and the blasting mat 2 becomes to maintain a firm posture to strong blasting pressure and vibration.

[0030] As described above, the blasting means is operated to blast the blasting means in a state that the blasting mat 2 provided to the blasting region 14 is pressed by the heavy duty equipment 3, and the explosives 15 a filled to each blasting hole 15 of the blasting region covered by the blasting mat 2 are successively blasted, and at this moment, the successively blasting explosives 15 a produces only crack without moving so that the base rock layer 1 of the blasting region 14 is completely divided from the cutting out surface 12, and the sand 15 b which has been filled to the blasting hole 15 upon blasting of explosive 15 a and blasting gas and blasting noise are moved to upward of the blasting hole as it accompanies strong pressure, and the steel plate member 21 of the blasting mat 2 which has covered the top surface of the blasting region 14 is made of steel plate of thickness capable of sufficiently bearing the blasting pressure, and since the waste tires 22 a being an elastic member 22 are not only a state closely adhered on top of the blasting region 14 but also even among the waste tires 22 a are closely adhered each other, the blasting pressure produced upon blasting of explosive 15 a and the flying sand flied away accompanying it and the blasting gas are not flied away or leaked out to exterior of the blasting mat 2, and since the waste tires 22 a being an elastic member 22 do an operation absorbing and relieving the blasting noise and vibration, the blasting noise and vibration transferred around blasting site can be remarkably decreased, and the blasting pressure of explosive 15 a is a degree capable of relieving to a state the base rock layer 1 desired to cut out is cracked from mother rock, and the blasting vibration is transferred only around of the blasting region 14 but it is not transferred to far away.

[0031] Thus, when the blasting work of the blasting region 14 of one place is finished, the blasting mat 2 is moved by heavy duty equipment 3 to next blasting region 14 and covered and the blasting work is progressed in stepwise and after the blasting works of all blasting region 14 of the base rock layer 1 are finished, the cutting out work of the base rock layer 1 is completed via means excavating the base rock layer of the blasting region 14 by heavy duty equipment such as braker, ripper and the like.

EXAMPLE

[0032] A blasting of base rock layer was tested as follows by applying the blasting method in accordance with the present invention, and measured results such as vibration and noise according to it is shown in table 1.

[0033] In accordance with above test results, maximum value of noise at facility distanced by 50 m from the blast working site was measured as 67.6 dB, and it did not exceeded 60 dB which was a noise permitting value at a time of usual conversation however it was detected further lower than 90 dB in which human and animal start to feel a pain by noise. Particularly, the noise of 10 m place neighbouring the working site was no more than 92.6 dB in maximum value and which was lower than 100 dB being a noise permitting value at a time of vehicle running on highway road, and the vibration was also detected as 0.1 cm/s at 50 m place, therefore it has shown that an influence giving to livestock was almost none in case when a cattle shed and the like were distanced apart more than 100 m from the working site.

[0034] Blasting Condition

[0035] Blast working object:

[0036] Hard rock layer (a working site of condition as FIG. 2 and FIG. 3) cutting slope width 25 m, height 15 m

[0037] Blasting hole piercing diameter and equipment: Φ51 mm, Crawler drill

[0038] Used explosive: Φ32 mm New MITE 5500

[0039] (product of Hankook gun powder co. ltd.)

[0040] Used detonator:

[0041] MS electric detonator(product of Hankook gun powder co. ltd.)

[0042] Blasting hole piercing depth:

[0043] Inner side hole 2.0 m, free surface side 3.0 m

[0044] Each blasting hole piercing distance:0.9 m

[0045] Blasting hole piercing number: 6 ea (2 row arrangement)

[0046] Blasting mat:

[0047] Steel plate thickness 3.5 mm, width 3.0 m, length 2.3 m, weight 2.2 ton

[0048] Top of the blasting mat is pressed by bucket of fork crane. TABLE 1 vibration, filling measuring value noise noise, quantity dB(A) measuring blasting per particle accelera dB(L) measur- instrument num- distance blasting speed frequency tion PVS storm ing kind bers (m) (kg) (cm/sec) (Hz) (g) (cm/sec) pressure location DS677 1 50 0.75 T: 0.038 >100 0.0298 0.110 67.6(A) 50 m (2506) V: 0.097 51 0.0331 place (german L: 0.070 73 0.0414 company 2 50 0.75 T: 0.041 39 0.0215 0.064 62.0(A) product) V: 0.046 47 0.0215 L: 0.080 32 0.0331 3 51 0.75 T: 0.079 39 0.0199 0.010 64.6(A) V: 0.048 73 0.0255 L: 0.052 34 0.0182 4 52 0.5 T: 0.051 37 0.0149 0.064 65.8(A) V: 0.030 47 0.0182 L: 0.048 34 0.0149 5 53 0.75 T: 0.083 27 0.0199 0.100 64.0(A) V: 0.091 51 0.0348 L: 0.083 32 0.0199 6 54 0.5 T: 0.054 37 0.0149 0.057 65.0(A) V: 0.045 51 0.0149 L: 0.040 39 0.0116 BMIII 1 30 0.75 T: 0.349 54 0.133 0.528 74.4(A) 30 m (BA5687) V: 0.351 85 0.196 place (german L: 0.394 45 0.116 company 2 31 0.75 T: 0.232 51 0.0928 0.375 74.49A) product) V: 0.322 54 0.166 L: 0.289 47 0.109 3 32 0.75 T: 0.195 60 0.0829 0.398 73.1(A) V: 0.230 43 0.113 0.398 73.1(A) L: 0.362 45 0.106 4 33 0.5 T: 0.140 57 0.0663 0.296 70.1(A) V: 0.162 39 0.0563 L: 0.254 43 0.0696 5 34 0.75 T: 0.325 47 0.106 0.568 69.6(A) V: 0.560 43 0.176 L: 0.378 39 0.109 6 35 0.5 T: 0.149 57 0.0729 0.269 68.0(A) V: 0.227 60 0.0795 L: 0.257 37 0.0696 BMIII 1 70 0.75 T: 0.079 38 0.0331 0.099 65.8(A) 70 m (BA5745) V: 0.081 51 0.0255 place (german L: 0.064 33 0.0331 company 2 70 0.75 T: 0.049 68 0.0331 0.083 61.2(A) product) V: 0.071 60 0.0265 L: 0.069 68 0.0331 3 2 0.75 Impossible 43 0.298 impossible 94.9(A) 2 m to 54 0.587 to place measure 37 0.324 measure 4 10 0.5 T: 1.80 49 1.35 2.00 91.5(A) V: 1.60 73 1.09 L: 1.59 73 0.981 5 10 0.75 T: 6.36 15.8 1.48 10.8 90.7(A) 10 m V: 9.86 19.7 5.57 place L: 6.12 15.1 3.13 6 10 0.5 T: 2.77 79 2.68 3.46 92.6(A) V: 2.60 64 2.01 L: 2.17 79 1.75

[0049] In accordance with the present invention as above, there is effect that in case when the blasting method using an explosive is executed in order to cut out one part of free surface of base rock layer made of hard rock layer to one side or both sides of road at a time of establishing construction work or expanding construction work of mountain road and seashore road, a mat body made of thick steel plate member and waste tire absorbing member are covered to working site, so that a phenomenon can be completely excluded in which flying stones are flied to residences or livestock facilities scattered to neighbour of the working site and at the same time the blasting noise or blasting vibration are remarkably decreased whereby not only casualty generation due to noise and vibration can be extremely minimized but also any influence is not given to public facility such as electric power transmitting tower whereby a part of free surface of the base rock layer can be slackened from mother rock, and since what the stones after blasting are flied away to exterior of mat body is isolated, there is effect that the base rock layer cutting work is made to be possible to progress without controlling the passing of vehicle on neighboring roads. And, since an operator of blasting site and the heavy duty equipment such as braker, ripper and the like excavating the blasted base rock layer are located at short distance(about 5-10 m) of the blasting site and thereby the blast working is executed, the excavating work can be speedily progressed by heavy duty equipment after the blasting work of blasting region is finished and thereby it brings an effect that working terms of cutting work of base rock layer can be reduced, and therefore it is a useful invention which makes to be able to excavate the base rock layer to a predetermined length by applying even to base rock layer formed to non-free surface. 

What is claimed is:
 1. A slackening type blasting method which makes base rock layer of blasting region to be cracked whereby slackening from mother rock comprising: a blasting hole piercing step for partitioning by equally dividing a blasting region at predetermined distance intervals toward lengthwise direction of base rock layer desired to excavate on horizontal top surface between free surface and cutting out surface of base rock layer and then piercing a number of blasting holes having a predetermined distance interval at every said blasting region toward vertical down direction a blasting lead wire connecting step in which an explosive inputted into the blasting hole pierced at said blasting hole piercing step is divided by each blasting region so as to be possible to blast, and which connects the blasting lead wire so that the explosives inputted into the blasting holes of each blasting region can be successively blasted in predetermined order a blasting mat providing step which provides a steel plate member having a magnitude capable of covering whole of multiple blasting holes formed at each blasting region connected with said blasting lead wire, and a blasting mat of weight material in which elastic member surrounding around blasting holes of blasting region is attached to bottom portion of said steel plate member and weight reinforcing member made of I type or H type beam being a weight material is welded in grid shape at top surface; and a blasting step for blasting an explosive by operating by blasting a blasting means connected with blasting mother line drawn out of blasting region provided with said blasting mat.
 2. A slackening type blasting method according to claim 1, wherein top surface of blasting mat is pressed by boom bar of crawler heavy duty equipment such as large type braker when blasting said blasting region. 